hey guys this the Q and the explained answer, i just dont know why they didnt just plug in the values with the 25s. here they focused on the constant gradient and stuff but i dont understand why?
The power varies with height (as you can see from the curve). If you plugged the numbers straight in, you’d get an average of the power from height = 0 to height = 10. This would be close to the correct answer (since the curve is close to being a straight line), but to find the power at 10m, you need to make a local approximation to a straight line, as shown in the solution.